On Whitechapel Road in the heart of the East End stands the East London Mosque.
For most of the 15,000 ordinary Muslims who pray there each week, it is simply a place of worship. For many, it provides valuable social facilities, and creche and outreach services.
But for a small number, the mosque is the headquarters of a secretive, fundamentalist political network. The Islamic Forum of Europe is dedicated, in its own words, to changing the "very infrastructure of society, its institutions, its culture, its political order and its creed … from ignorance to Islam".
The mosque and IFE are inextricably intertwined. Dr Mohammed Abdul Bari, the chairman of the mosque, and its vice-chairman are former IFE presidents.